The objective of this project is to study the calcium ion-induced fluoride release from fluorine-carrying copolymers and polyvinylphosphonates. These polymers, which have been shown to absorb on tooth enamel, could thus act as slow fluoride-releasing agents, and would combine the caries preventative properties of polyphosphonates and of fluoride ions. Copolymers of vinylphosphonyl dichloride with vinylphosphonyl difluoride and with vinylphosphonyl thiodifluoride have been synthesized. Following initial hydrolysis of these copolymers, the corresponding slow fluoride-releasing polyvinyl phosphonates have been formed. The kinetics of the fluoride release for these copolymers in homogenous solution and on the surface of tooth enamel are being studied. The analytical techniques used include potentiometry, internal reflection infrared absorption spectroscopy, auger spectroscopy, and electron probe x-ray fluorescence. In the first nine months of this project, the synthesis of the copolymers was completed, and the appropriate analytical techniques were tested for their adequacy to our problem. The kinetics of the calcium-induced fluoride release reaction will be studied in the follow-on phase of this project, as will be the nature of the fluoride carrier in the tooth enamel.